Polyester Composition with Improved Dyeing Properties

Abstract

A composition with advantages for textile fibers is disclosed. The composition is a melt of polyester precursors selected from the group consisting of terephthalic acid, dimethyl terephthalate, ethylene glycol, sebacic acid in an amount sufficient to give filaments and fibers made from the melt a dye receptivity similar to cotton at atmospheric pressure; pentaerythritol in an amount sufficient to give pill resistance to yarns blended of cotton with fibers made from the melt, and polyethylene glycol in an amount sufficient to give the melt the elasticity necessary to produce extruded filament from the melt. In an exemplary embodiment, the copolymer melt includes between about 4 and 6 percent sebacic acid, between about 500 and 800 ppm pentaerythritol, and between about 3.5 and 3.9 percent polyethylene glycol, with less than 2 percent DEG, at an intrinsic viscosity of between about 0.640 and 0.690 dl/g, and at a temperature of between about 268° C. and 271° C., with the proportional amounts being based on the amount of polymerized copolymer.

1 . A copolymer composition with advantages for textile fibers, and consisting essentially of a melt of:
 polyester precursors selected from the group consisting of terephthalic acid, dimethyl terephthalate, and ethylene glycol;   between about 4 and 6 percent sebacic acid based on the amount of copolymer;   between about 500 and 800 parts per million (ppm) of pentaerythritol based on the amount of copolymer; and   between about 3.5 and 3.9 percent polyethylene glycol based on the amount of copolymer;   diethylene glycol (DEG) in an amount of less than 2 percent based upon the amount of copolymer; and   said melt being maintained at a temperature of between about 268° C. and 271° C., and at an intrinsic viscosity of between about 0.640 and 0.690 dl/g.   
     
     
         2 . A copolymer composition according to  claim 1  comprising:
 about 4 percent sebacic acid based on the amount of copolymer; 
 about 500 parts per million (ppm) of pentaerythritol based on the amount of copolymer; and 
 about 3.5 percent polyethylene glycol based on the amount of copolymer. 
 
     
     
         3 . A copolymer composition according to  claim 1  comprising:
 about 5 percent sebacic acid based on the amount of copolymer; 
 about 500 parts per million (ppm) of pentaerythritol based on the amount of copolymer; and 
 about 3.6 percent polyethylene glycol based on the amount of copolymer. 
 
     
     
         4 . A copolymer composition according to  claim 1  comprising:
 about 6 percent sebacic acid based on the amount of copolymer; 
 about 800 parts per million (ppm) of pentaerythritol based on the amount of copolymer; and 
 about 3.7 percent polyethylene glycol based on the amount of copolymer; 
 
     
     
         5 . A copolymer composition according to  claim 1  comprising:
 about 4 percent sebacic acid based on the amount of copolymer; 
 about 800 parts per million (ppm) of pentaerythritol based on the amount of copolymer; and 
 about 3.8 percent polyethylene glycol based on the amount of copolymer. 
 
     
     
         6 . A copolymer composition according to  claim 1  comprising:
 about 5 percent sebacic acid based on the amount of copolymer; 
 about 800 parts per million (ppm) of pentaerythritol based on the amount of copolymer; and 
 about 3.9 percent polyethylene glycol based on the amount of copolymer. 
 
     
     
         7 . A copolymer composition according to  claim 1  comprising:
 about 6 percent sebacic acid based on the amount of copolymer; 
 about 800 parts per million (ppm) of pentaerythritol based on the amount of copolymer; and 
 about 3.9 percent polyethylene glycol based on the amount of copolymer. 
 
     
     
         8 . A polyester copolymer filament consisting essentially of between about 4 and 6 percent sebacic acid;
 between about 500 and 800 ppm pentaerythritol;   between about 3.5 and 3.9 percent polyethylene glycol;   with less than 2 percent DEG,   and with the proportional amounts being based on the amount of polymerized copolymer.   
     
     
         9 . A textured polyester copolymer filament yarn according to  claim 8 . 
     
     
         10 . A textured staple fiber formed from the polyester copolymer filament of  claim 8 . 
     
     
         11 . A blended yarn formed from cotton and the textured polyester copolymer staple fiber of  claim 10 . 
     
     
         12 . A blended yarn according to  claim 11  in which the cotton is present in the range of between about 40 and 60% by weight. 
     
     
         13 . A dyed fabric formed from the blended yarn of  claim 13 . 
     
     
         14 . A method of spinning a polyester copolymer filament comprising the steps of:
 polymerizing terephthalic acid, ethylene glycol, between about 4 and 6 percent sebacic acid, between about 500 and 800 ppm pentaerythritol, and between about 3.5 and 3.9 percent polyethylene glycol to a copolymer melt;   with less than 2 percent DEG;   at an intrinsic viscosity of between about 0.640 and 0.690 dl/g;   and at a temperature of between about 268° C. and 271° C.;   with the proportional amounts being based on the amount of polymerized copolymer.   
     
     
         15 . A method according to  claim 14  further comprising the steps of extruding and quenching the copolymer polyester filament. 
     
     
         16 . A method according to  claim 15  further comprising the step of texturing the quenched copolymer polyester filament. 
     
     
         17 . A method according to  claim 16  further comprising cutting the textured copolymer polyester filament into staple fiber. 
     
     
         18 . A method according to  claim 17  further comprising blending the cut staple polyester copolymer with cotton fibers into a blended yarn. 
     
     
         19 . A method according to  claim 18  further comprising
 forming a fabric from the blended yarn; and 
 thereafter dying the blended fabric with a dye selected from the group consisting of disperse dyes, reactive dyes, and successive steps of disperse and reactive dyes.